| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2001: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2000: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
Algicidal substances to a harmful flagellate, Heterosigma akashiwo, in the autolysates of two species of jellyfish, Carybdea rastoni and Chrysaora melanester, were isolated by sequential procedures consisting of Bligh-Dyer's method, silica gel-TLC, and HPLC on a gel filtration column (Superdex peptide HR10/30) and on reverse phase column (L-column, ODS). Judging from the chromatographic behavior and LC-MS analysis of the isolated substances, it was suggested that five kinds of algicides from C. rastoni were Docosahexanoic acid (M : W=328, 22 : 6), Eicosapentaenoic acid (M.W=302, 20 : 5), Heptadecamonoenoic acid (M.W=268, 17 : 1), Triacylglycerols with M.W of 344 (C number of R1+R2+R3 was 13 and 7 of double bond) and 346 (C number of R1+R2+R3 was 13 and 6 of double bond), and that an algicide from C. melanaster was Tetradecsaheptaenoic acid (M.W=227, 15 : 7).
A toxic flagellate Heterocapsa circularisquama is known to kill shellfish, such as oyster and a mother-of-pearl. The test was conducted to know whether the algicide (cis-5, 8, 11, 14, 17-icosapentanoic acid) of the jellyfish Aurelia aurita can kill toxic flagellate cells within oyster and a mother-of-pearl. Number of cells of H. circularisquama in the two shellfish species soaked in seawater added with autolysate of the jellyfish (final concentration ; 5 % v/v) decreased to 10-40 % of the initial number after 8 hours and to 5 % of the initial after 13 hours, without killing no shellfish during experiments. The present treatment is expected to utilize for reducing propagation of shellfishes infected with toxic flagellates.
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